Luigi Mangione arrest: UnitedHealthcare CEO murder suspect's lawyer has seen 'no evidence' linking gun to New York

The defense attorney representing Luigi Mangione , the suspect in the killing of UnitedHealthcare CEO Brian Thompson , said he has seen "no evidence" linking his client to the killing, adding that "a lot of guns look the same."

"I have not been made aware of any evidence that links the gun that was found on his person to the crime so these are things that we're looking to see," attorney Thomas Dickey told ABC News' "Good Morning America" on Wednesday.

"Today's another day," he added. "We're looking forward to beginning our inquiry as to what evidence may or may not be out there."

Mangione, 26, plans to challenge his extradition from Pennsylvania to New York , where he faces a charge of second-degree murder in connection with Thompson's Dec. 4 outside a Midtown Manhattan hotel.

Mangione was arrested on Monday in Altoona, Pennsylvania, and charged in Pennsylvania for allegedly possessing an untraceable "ghost" gun."

"He has constitutional rights and that's what he's doing" in challenging the interstate transfer, Dickey told reporters on Tuesday.

Police officials in New York have not said whether the gun recovered in Pennsylvania is considered a match for the one used in the killing last week, but said it looks similar and that it would undergo ballistic testing.

"A lot of guns look the same," Dickey said on Wednesday. "If you brought a gun in and said, 'Well, it looks like that,' I don't even know if that evidence would be admissible. So I would argue it wouldn't be given much weight."

He also cautioned that anyone speculating on the case should take the potential evidence "in its entirety," not taking pieces of writing or other evidence "out of context."

"People put out certain things, parts of different things," he said. "I think any lawyer involved in this situation would want to see it all."

Mangione plans to plead not guilty to the charges filed against him in Pennsylvania, Dickey said. A judge has ordered Mangione held without bail/

The Manhattan District Attorney's Office said it will seek a governor's warrant to try to force Mangione's extradition. New York Gov. Kathy Hochul said in a statement that she'll sign a request for the governor's warrant "to ensure this individual is tried and held accountable."

Dickey said he anticipates that Mangione would also plead not guilty to the second-degree murder charge in New York.

The attorney said he has limited information about the facts of the New York murder case but he conceded Mangione is "accused of some serious matters." He added that Mangione is "taking it as well as he can."

Mangione yelled to the press about "an insult to the intelligence of the American people" as he was physically dragged into the courthouse on Tuesday.

When Mangione was arrested on Monday, he had "written admissions about the crime" with him, according to the New York arrest warrant.

Mangione's writings, obtained by ABC News, addressed to the "Feds," said, "I do apologize for any strife of traumas but it had to be done. Frankly, these parasites simply had it coming."

He claimed that the U.S. has the most expensive health care system in the world, but ranks about No. 42 in life expectancy. He said UnitedHealthcare "has grown and grown, but as our life expectancy? No the reality is, these [ indecipherable ] have simply gotten too powerful, and they continue to abuse our country for immense profit."

Mangione appears to have been inspired by the Unabomber , according to an NYPD intel analysis report obtained by ABC News.

The report warned that like Ted Kaczynski -- whose 17-year bombing campaign killed three and injured 23 people -- Mangione may become a "martyr" who inspires "a wide range of extremists" to act.

ABC News' Peter Charalambous and Josh Margolin contributed to this report.

On Tuesday, Pennsylvania State Police released a new photograph of Mangione, wearing a blue medical mask, dark jacket and brown beanie, and eating what appears to be a McDonald's hash brown, to jog anyone's memory who may have seen him in Pennsylvania since last Wednesday

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Along with a second-degree murder charge, he also has three gun charges -including unlawful possession of a loaded firearm and possession of a suppressor -- and a charge of possession of a forged instrument.

The forged instrument is the fake New Jersey driver's license he allegedly used to check into the hostel on the Upper West Side.

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A grandson of a wealthy, self-made real estate developer and philanthropist, Mangione is a cousin of a current Maryland state legislator. Mangione was valedictorian at his elite Baltimore prep school, where his 2016 graduation speech lauded his classmates' "incredible courage to explore the unknown and try new things."

He went on to earn undergraduate and graduate degrees in computer science in 2020 from the University of Pennsylvania, a spokesperson said.

"Our family is shocked and devastated by Luigi's arrest," Mangione's family said in a statement posted on social media late Monday by his cousin, Maryland lawmaker Nino Mangione. "We offer our prayers to the family of Brian Thompson and we ask people to pray for all involved."

The mother of Mangione filed in November a missing person report in San Francisco, seeking info on the 26-year-old, according to two law enforcement sources.

Repeated requests for information about the report went unanswered by the San Francisco Police Department. Both the chief and the spokesman referred questions to the NYPD.

The Associated Press and ABC News contributed to this report.

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